Effects of Reaction Conditions on the Formation of Furfural Compounds in Maillard Reaction System of Glucose-Glycine

The Maillard reaction system of glucose and glycine was applied to study the formations of furfural compounds. The effects of glucose/glycine molar concentration ratio, initial pH, heating temperature and time on the formations of 5-hydroxymethylfurfural (HMF), 2-furfural (F) and 5-methyl-2-furfural (MF) were evaluated. The kinetic equations of HMF, F and MF were established and their apparent activation energies were also predicted. The results showed that: Glucose/glycine molar concentration ratio had great influence on the formations of furfural compounds. The formation of HMF continued to increase with the increase of ratio, and the formations of F and MF reached the maximum when the ratio was 1:1. The acidic pH conditions could promote the formation of HMF, while the neutral and alkaline pH conditions were conducive to the formation of F. The total amount of furfural compounds decreased rapidly with the increase of pH. The amounts of HMF, F, and MF in the glucose-glycine reaction system increased with the increase of heating temperature and time. The formations of HMF and F in glucose and glycine model followed first-order kinetics model at lower temperatures (HMF: 70~110 ℃; F: 70 ℃), while their formations were in accordance with zero-order kinetics model at higher temperatures (HMF: 130 ℃; F: 90~130 ℃). The formation of MF followed zero-order kinetics model at 90~130 ℃. The results would provide guidance on the production and control of HMF, F, and MF in the food thermal processing industry.